Poly(ethylene terephthalate)(apet) multilayer oxygen-scavenging containers and methods of making

ABSTRACT

An oxygen-scavenging multi-layer container and methods of making, controlling, and using the same are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is application which claims the priority to U.S. ProvisionalApplication No. 61/774,109, filed Mar. 7, 2013, the entire disclosuresof which are expressly incorporated herein by reference.

TECHNICAL FIELD

Described herein are multi-layer containers usable in the plasticspackaging industry. Further disclosed are methods of making and usingmulti-layer containers with oxygen-scavenging properties and methods ofcontrolling the oxygen scavenging incubation period of multi-layercontainers.

BACKGROUND OF THE INVENTION

In food and beverage packaging, metal cans and glass bottles weretraditionally the preferred packages. With the introduction ofpolypropylene (PP) and ethylene vinyl alcohol copolymer (EVOH)multi-layer containers, PP/EVOH containers, and poly(ethyleneterephthalate) PET containers in the 1980s, a portion of the metal-basedand glass-based packages were replaced by plastics-based packages.

The shelf life of a plastic package is determined by the amount ofoxygen that permeates into the package. A container made from amorphouspoly(ethylene terephthalate) (APET) typically has a shelf life of threeto six months. A container made from crystalline poly(ethyleneterephthalate) (CPET) typically has a shelf life of five to ten months.Because both APET and CPET containers have a PET recycling code (“1”),which is considered most environmental friendly due to the successfuldevelopment of recycling infrastructure over the years; it would bedesirable to improve the oxygen barrier of these materials so they canbe used extensively in packaging for food and other oxygen-sensitiveproducts. Many unsuccessful attempts have been made at incorporating aneffective oxygen scavenger into the walls of PET containers such thatthe container has zero or negative oxygen permeation to compete with themetal-based and glass-based packages.

Not only do commercially available oxygen scavenging containers fallshort of achieving zero or negative oxygen permeation, but they haveseveral other drawbacks. For instance, many articles of active packagingsuffer from two oxygen absorption initiation problems: (1) short or noinduction period and (2) long or infinite induction period. When theinduction period is too short, it allows for ambient oxygen absorptionduring inventory before the container is filled (i.e., before oxygenabsorption is desired). On the other hand, when the induction period istoo long, they require some sort of triggering agent, such asultraviolet light or water, to begin scavenging. A further disadvantageof these containers is that such materials may require thick sidewalls,which adds to cost.

Many commercially available oxygen-scavenging containers begin toscavenge oxygen immediately. Without an incubation period, the expensiveoxygen scavenger is wasted during the inventory period. It is common inthe industry for containers to be in transportation from supplier touser for a couple months. It is therefore desirable to keep thecontainer from scavenging oxygen during inventory and start oxygenscavenging immediately when the container is filled with product.

It would be beneficial to develop a plastics-based package for food orbeverages with less oxygen permeation and more controlled oxygenscavenging. There remains a need for packaging materials that performthese feats in a more efficient and cost-effective manner. It would bebeneficial to improve the shelf life of containers made specificallyfrom PET-based materials. It would be further beneficial to discoverefficient methods of manufacturing such containers.

There is no admission that the background art disclosed in this sectionlegally constitutes prior art.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein is a multi-layer container usable in plastics packagingfor food and beverages. The multi-layer container comprises an outerlayer and an inner layer, each including a polymeric resin, and a middlelayer.

Further disclosed is a method of using a multi-layer container describedherein.

Various objects and advantages of this invention will become apparent tothose skilled in the art from the following detailed description of thepreferred embodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing oxygen ingress into empty containers overtime. The graph shows negative oxygen permeation of an empty multilayercontainer comprised of 60% CPET/20%(10%BB-10™+90%Merge™)/20% APET,compared to linearly increasing oxygen permeation in a controlcontainer.

FIG. 2 is a graph displaying barrier properties of retorted,water-filled containers. The graph compares the percent of oxygeningress over time between a CPET multi-layer container (comprised of 60%CPET/20% (10%BB-10™ component+90%Merge™ component)/20% APET), a controlcontainer, and a PP/EVOH container. The containers were retorted at 260°F. for 45 minutes.

FIG. 3 is a graph showing percent oxygen absorption over time, for amulti-layer container (comprised of 60% CPET/20% (20%BB-10™component+80%Merge™ component)/20% APET) not designed to have asignificant incubation period.

FIG. 4 is a graph showing percent oxygen absorption over time, for amulti-layer container (comprised of 60% CPET/20% (40%BB-10™component+60%Merge™ component)/20% APET), designed to have an incubationperiod of about 50 days.

FIG. 5A is a graph showing the effect of the scavenging componentabsorption of a multi-layer container, an APET control container, and amonolayer container, where the total concentration of scavenging polymerin the multi-layer container and monolayer container is 1%.

FIG. 5B is a table of the data shown in FIG. 5A.

FIG. 6A is a graph showing the oxygen absorption of a multi-layercontainer, an APET control container, and a monolayer container, wherethe total concentration of scavenging polymer in the multi-layercontainer and monolayer container is 2%.

FIG. 6B is a table of the data shown in FIG. 6A.

FIG. 7A is a graph showing the oxygen absorption of a multi-layercontainer, an APET control container, and a monolayer container, wherethe total concentration of scavenging polymer in the multi-layercontainer and monolayer container is 3%.

FIG. 7B is a table of the data shown in FIG. 7A.

FIG. 8A is a graph showing the oxygen permeation of a multi-layercontainer, an APET control container, and a monolayer container, wherethe total concentration of scavenging polymer in the multi-layercontainer and monolayer container shown is 1%.

FIG. 8B is a table of the data shown in FIG. 8A.

FIG. 9A is a graph showing the oxygen permeation of a multi-layercontainer, an APET control container, and a monolayer container, wherethe total concentration of scavenging polymer in the multi-layercontainer and monolayer container shown is 2%.

FIG. 9B is a table of the data shown in FIG. 9A.

FIG. 10A is a graph showing the oxygen permeation of a multi-layercontainer, an APET control container, and a monolayer container, wherethe total concentration of scavenging polymer in the multi-layercontainer and monolayer container shown is 3%.

FIG. 10B is a table of the data shown in FIG. 10A.

FIG. 11A is a graph showing oxygen absorption as a function of BB-10®component concentration in a middle layer of an APET multi-layercontainer. Absorption capacity tends to increase as the concentration ofBB-10™ component in the middle layer increases.

FIG. 11B is a table of the data shown in FIG. 11A.

FIG. 12 is a table showing the data shown in FIG. 11A and FIG. 11B as afunction of time, showing a total BB-10™ component concentration in thecontainer sidewall and the absorption capacity (cc/g of BB-10™component).

FIG. 13A is a graph showing the effect of layer structure on oxygenpermeation, where the thickness of the outer layer in the APETmulti-layer containers shown is 2.2 mils.

FIG. 13B is a table of the data shown in FIG. 13A.

FIG. 14A is a graph showing the effect of layer structure on oxygenpermeation, where the thickness of the outer layer in the APETmulti-layer containers shown is 4.4 mils.

FIG. 14B is a table of the data shown in FIG. 14A.

FIG. 15A is a graph showing the effect of layer structure on oxygenpermeation, where the thickness of the outer layer in the APETmulti-layer containers shown is 6.6 mils.

FIG. 15B is a table of the data shown in FIG. 15A.

FIG. 16 is a table summarizing the effect of the outer layer permeationrate on the headspace oxygen absorption for the data shown in FIGS.13A-13B, 14A-14B, and 15A-15B.

FIG. 17A is a graph showing the effect of the scavengingpolymer-to-catalyst concentrate ratio on the oxygen absorption continuesover time for multi-layer container (#10446) having the layers: 12 milCPET/4 mil blend (10% BB-10™ component+90% Merge™ component)/4 mil APET;where the container has 2% total BB-10™ component, and for multi-layercontainer (#Oxy 2) having the layers: 12 mil CPET/2 mil blend (20%BB-10™ component+80% Merge™ component)/6 mil APET; where the containerhas 2% total BB-10™ component, for over 100 days.

FIG. 17B is a table of the data shown in FIG. 17A.

FIG. 18A is a graph showing the effect of the storage time-on the oxygenabsorption over time for multi-layer container (#10446) having thelayers: 12 mil CPET/4 mil blend (10% BB-10™ component+90% Merge™component)/4 mil APET; where the container has 2% total BB-10™component.

FIG. 18B is a table of the data shown in FIG. 18A.

FIG. 19A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy2) having thelayers: 12 mil CPET/2 mil blend (20% BB-10™ component+80% Merge™component)/6 mil APET; where the container has 2% total BB-10™component.

FIG. 19B is a table of the data shown in FIG. 19A.

FIG. 20A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy 3) having thelayers: 12 mil CPET/4 mil blend (20% BB-10™ component+80% Merge™component)/4 mil APET; where the container has 4% total BB-10™component.

FIG. 20B is a table of the data shown in FIG. 20A.

FIG. 21A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy 4) having thelayers: 12 mil CPET/2.7 mil blend (30% BB-10™ component+70% Merge™component)/5.3 mil APET; where the container has 4% total BB-10™component.

FIG. 21B is a table of the data shown in FIG. 21A.

FIG. 22A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy 5) having thelayers: 12 mil CPET/2 mil blend (40% BB-10™ component+60% Merge™component)/6 mil APET; where the container has 4% total BB-10™component.

FIG. 22B is a table of the data shown in FIG. 22A.

FIG. 23 is table summarizing the data of FIGS. 18A-18B, FIGS. 19A-19B,FIGS. 20A-20B, FIGS. 21A-21B and FIGS. 22A-22B showing the effect ofvarying the scavenging component-to-catalyst concentrate ratio on theoxygen absorption, where data was gathered from each container beginningafter two different storage times.

FIG. 24A is a graph showing the effect of varying the storage time onthe oxygen permeation for a multi-layer container having the layers: 6.6mil APET/2.2 mil blend (25% BB-10® component+75% Merge® component/2.2mil APET, where the container has 5% total BB-10® component; data wasgathered from each container after two different storage times.

FIG. 24B is a table of the data shown in FIG. 24A.

FIG. 25A is a graph showing the effect of varying the storage time onthe oxygen permeation for a multi-layer container having the layers: 6.6mil APET/1.7 mil blend (33% BB-10® component+67% Merge® component/2.7mil APET, where the container has 5% total BB-10 component; data wasgathered from each container after two different storage times.

FIG. 25B is a table of the data shown in FIG. 25A.

FIG. 26A is a graph showing the effect of varying the storage time onthe oxygen permeation for a multi-layer container having the layers: 6.6mil APET/1.13 mil blend (50% BB-10® component+50% Merge® component/3.3mil APET, where the container has 5% total BB-10® component; data wasgathered from each container after two different storage times.

FIG. 26B is a table of the data shown in FIG. 26A.

FIG. 27 is a table summarizing the data of FIGS. 24A-24B, FIGS. 25A-25Band FIGS. 26A-26B, showing the effect of varying the scavengingpolymer-to-catalyst concentrate ratio on the transition time of positiveoxygen permeation to negative oxygen permeation for a multi-layercontainer having the layers.

DETAILED DESCRIPTION OF THE INVENTION

Described herein is an oxygen-scavenging multi-layer container orarticles for use in the plastics packaging industry. In certainembodiments, the multi-layer container has zero oxygen permeation formore than three years. In addition, the composition of the multi-layercontainer allows the multi-layer container to reduce headspace oxygenafter being sealed. Also, described herein is a method of controllingthe incubation period of the multi-layer container's oxygen scavengingactivity.

As used herein, “polymer” may be used to refer to homopolymers,copolymers, interpolymers, etc. Likewise, a “copolymer” may refer to apolymer comprising two monomers or to a polymer comprising three or moremonomers.

As used herein, “middle” or “intermediate” is defined as the position ofone layer of a multi-layer article wherein such layer lies between twoother identified layers. In certain embodiments, the intermediate layermay be in direct contact with either or both of the two identifiedlayers (e.g., outer layer and inner layer). In other embodiments, one ormore additional layers may also be present between the intermediatelayer and either or both of the two identified layers.

As used herein, the middle, or active, layer includes at least oneoxygen scavenging component and at least one catalyst-containingconcentrate. It is to be understood herein that the terms “middlelayer,” “intermediate” and “active layer” may be used interchangeably,and further that the “middle layer” while generally understood to beinterposed between an outermost layer and at an innermost layer, such“middle layer” need not necessarily be exactly centered between theouter layer and the inner layer. That is, in multi-layer containers thatcontain an even number of layers, the middle layer may be positionedeither closer to the outer layer, or to the inner layer, depending onthe end-use requirements of the multi-layer container.

Any of the layers in the multi-layer container may comprise a pluralityof polymeric resins and may include any of several additives, andnumerous embodiments of the multi-layer container are disclosed herein.In addition, several characteristics of the multi-layer container arecontrollable by adjusting the thickness ratio of the layers, the totalconcentration of at least one oxygen scavenging component, the ratio ofscavenging component to a catalyst-containing concentrate and/or theidentity of specific resins in each layer.

In a broad aspect, the multi-layer container is a modified, or active,polymeric resin container. The container comprises an outer layer, amiddle layer, and an inner layer. In certain embodiments. The middlelayer is generally not thicker than either of the outer or inner layers.In one embodiment, the thickness of the layers, from outer to inner, isin a 60:20:20 ratio. Other thickness ratios are possible. For example,the layers may be in a 40:20:40 thickness ratio, a 60:13:27 thicknessratio, or a 60:10:30 thickness ratio. In certain embodiments, themulti-layer container disclosed herein has a total sidewall thickness(meaning the thicknesses of each layer combined) of about 10 mils toabout 30 mils, though other thicknesses are possible.

The outer layer and inner layer are each comprised of a polymeric resin.Either layer may comprise a single resin or a blend of multiple resins.Suitable resins for use in the inner or outer layers are PET, PP, EVOH,high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-densitypolyethylene (LDPE), polystyrene (PS), acrylic, nylon, polycarbonate,polylactic acid, acrylonitrile butadiene styrene (ABS), or mixturesthereof. In certain embodiments, the polymeric resin is crystalline PET(CPET). In one embodiment, referred to herein as a CPET multi-layercontainer, the outer layer comprises CPET and the inner layer comprisesAPET.

The middle, or active, layer of the multi-layer container includes atleast one oxygen-scavenging component (also referred to herein as“scavenging polymer” and “scavenging component”) and at least onecatalyst-containing concentrate. The scavenging component andcatalyst-containing concentrate are blended together in a desired ratioto form the middle layer. The scavenging component is present in aconcentration ranging from about 1% to about 50%, by weight, of thetotal container. In certain embodiments, the scavenging component ispresent in a concentration ranging from about 1% to about 10%, byweight, of the total container. As the examples below demonstrate, theamount of oxygen absorbed by the multi-layer container is determined bythe total amount of the scavenging component in the multi-payercontainer.

In another aspect, provided herein is a method of increasing theabsorption of oxygen by a multi-layer container, the method comprisingincreasing the concentration of scavenging component present in themiddle layer.

In a particular embodiment, the multi-layer container comprising anouter layer, an inner layer, and at least one middle layer interposedtherebetween; the middle layer including a blend of: i) at least oneoxygen-scavenging component, and ii) at least one catalyst-containingconcentrate; wherein middle layer contains at least one catalysttransition metal up to about 3% by weight of the multi-layer container.

In certain embodiments, the catalyst-containing concentrate includes oneor more oxidation catalysts.

In certain embodiments, the catalyst-containing concentrate depends onthe makeup of the scavenging component.

In certain embodiment, the catalyst-containing concentrate depends onthe ability to co-process (e.g. co-extrusion or co-injection) with thescavenging component.

In certain embodiments, the catalyst-containing concentrate includes atransition metal selected from cobalt, copper, rhodium, ruthenium,palladium, tungsten, osmium, cadmium, silver, tantalum, hafnium,vanadium, titanium, chromium, nickel, zinc, and manganese.

In certain embodiments, the catalyst-containing concentrate includes atransition metal in the form of a salt.

In certain embodiments, the catalyst-containing concentrate includes atransition metal in the form of a salt, and wherein counter ions for themetal include one or more of carboxylates, including neodecanoates,octanoates, stearates, acetates, naphthalates, lactates, maleates,acetylacetonates, linoleates, oleates, palminates, and 2-ethylhexanoates; oxides; borides; carbonates; chlorides; dioxides;hydroxides; nitrates; phosphates; sulfates; and, silicates.

In certain embodiments, the catalyst-containing concentrate includes atleast one of cobalt stearate or cobalt acetate that is present in atotal concentration not exceeding about 3%, by weight, of themulti-layer container.

In certain embodiments, catalyst-containing concentrate is comprised ofan oxidation catalyst blended with a polymeric resin.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 5:95.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 10:90.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 20:80.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 30:70.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 40:60.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 50:50.

In certain embodiments, a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 60:40.

In certain embodiments, a total concentration of oxygen-scavengingcomponent in the middle layer is at least about 10%, by weight, of themulti-layer container.

In certain embodiments, a total concentration of oxygen-scavengingcomponent in the middle layer is at least about 5%, by weight, of themulti-layer container

In certain embodiments, a total concentration of oxygen-scavengingcomponent in the middle layer is at least about 3%, by weight, of themulti-layer container.

In certain embodiments, a total concentration of oxygen-scavengingcomponent in the middle layer is at least about 2%, by weight, of themulti-layer container.

In certain embodiments, a total concentration of oxygen-scavengingcomponent in the middle layer is at least about 1%, by weight, of themulti-layer container.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of no greater than about 3 cc O₂/100in²·day·atm.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of no greater than about 2 cc O₂/100in²·day·atm.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of no greater than about 1.5 cc O₂/100in²·day·atm.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of no greater than about 1 cc O₂/100in²·day·atm.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of no greater than about 0.5 cc O₂/100in²·day·atm.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of no greater than about 0 cc O₂/100in²·day·atm.

In certain embodiments, the outer layer of the multi-layer container hasan oxygen permeation rate of less than about 0 cc O₂/100 in²·day·atm.

In certain embodiments, the multi-layer container has an oxygenheadspace absorption effect of about 0 cc O₂ ingress after about 5 days.

In certain embodiments, the multi-layer container has an oxygenheadspace absorption effect of less than about 0 cc O₂ ingress afterabout 5 days.

In certain embodiments, the multi-layer container has an oxygenheadspace absorption effect of more than about 0.3% headspace oxygenreduction after about 20 days.

In certain embodiments, the multi-layer container has an oxygenabsorption effect of that increases over time after about 5 days aftermanufacturing of the multi-layer container.

In certain embodiments, the middle layer has an oxygen-scavengingcomponent to catalyst-containing concentrate ratio of greater than about0.05.

In certain embodiments, substantially no adhesive material is interposedbetween the middle layer and the outer layer and/or the middle layer andthe inner layer.

In certain embodiments, a multi-layer container comprises an outerlayer, an inner layer, and at least one middle layer interposedtherebetween; the middle layer including a blend of: i) at least oneoxygen-scavenging component, and ii) at least one catalyst-containingconcentrate; wherein middle layer contains at least one catalysttransition metal up to about 3%, by weight, of the multi-layercontainer; the multi-layer container having: i) a ratio ofoxygen-scavenging component to catalyst-containing concentrate of about5:95; ii) a total concentration of oxygen-scavenging component in themiddle layer of at least about 1%, by weight, of the multi-layercontainer; iii) an oxygen permeation rate of the outer layer no greaterthan about 3 cc O₂/100 in²·day·atm; iv) an oxygen headspace absorptioneffect of about 0 cc O₂ ingress after about 5 days; and v) an oxygenabsorption effect of that increases over time after about 5 days aftermanufacturing of the multi-layer container.

Also described herein is a method of making the multi-layer container,comprising: providing a middle layer including a blend of: i) at leastone oxygen-scavenging component; and, ii) at least onecatalyst-containing concentrate that contains at least one catalysttransition metal up to about 3%, by weight, of the multi-layercontainer; and, interposing the middle layer between at least one outerlayer and at least one inner layer without the use of an adhesivematerial.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET).

In certain embodiments, both the outer layer and the inner layer arecomprised of an amorphous poly(ethylene terephthalate) polymer (APET).

In certain embodiments, at least one of the inner layer and the outerlayer is comprised of APET, and the blend of the oxygen-scavengingpolymer and the catalyst-containing concentrate is present in the middlelayer at about a 50:50 ratio.

In certain embodiments, at least one of the inner layer and the outerlayer is comprised of APET, and the blend of the one oxygen-scavengingpolymer and the catalyst-containing concentrate is present in the middlelayer at about a 50:50 ratio; and wherein the middle layer has athickness of about 0.5 mil.

In certain embodiments, at least one of the inner layer and the outerlayer is comprised of APET, the blend of the one oxygen-scavengingpolymer and the catalyst-containing concentrate is present in the middlelayer at about a 50:50 ratio; and, the multi-layer container having anoxygen absorption of about 50 cc O₂, per gram of oxygen-scavengingpolymer, present in the multi-layer container.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the outer layer has a thickness of about 1 mil or more.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the oxygen-scavenging polymer in the middle layer is presentat least about 0.5%, by weight, of the multi-layer container.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the oxygen-scavenging component to catalyst-containingconcentrate in the middle layer is present at least about 1%, by weight,of the multi-layer container.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the oxygen-scavenging polymer in the middle layer is presentat least about 2%, by weight, of the multi-layer container.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the oxygen-scavenging component polymer in the middle layeris present at least about 2%, by weight, of the multi-layer container.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and a ratio of the oxygen-scavenging component present tocatalyst-containing concentrate in the middle layer is about a 5:95ratio.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the oxygen-scavenging component present at least about 2% orgreater, by weight, of the multi-layer container.

In certain embodiments, at least one of the outer layer and the innerlayer is comprised of an amorphous poly(ethylene terephthalate) polymer(APET), and the multi-layer container has an oxygen absorption of atleast about 50 cc O₂, per gram of oxygen-scavenging component.

Oxygen Scavenger Component

In one non-limiting example, the oxygen scavenger component generallycomprises a copolyester ether having a polyether segment comprising apoly(tetramethylene-co-alkylene ether), where the alkylene is selectedfrom the group consisting of ethylene, propylene and butylene. Themolecular weight of the polyether segment can be in the range of fromabout 200 g/mole to about 5,000 g/mole. The copolyester ether cancontain the polyether segment in a range of from about 15%, by weight,to about 95%, by weight. The copolyester ether further comprises apoly(alkylene oxide)glycol selected from the group includingpoly(ethylene oxide)glycol, poly(trimethylene oxide)glycol,poly(tetramethylene oxide)glycol, poly(pentamethylene oxide)glycol,poly(hexamethylene oxide)glycol, poly(heptamethylene oxide)glycol,poly(octamethylene oxide)glycol, and poly(alkylene oxide) glycolsderived from cyclic ether monomers where the alkylene is selected fromthe group including ethylene, propylene and butylene. The mole percentof alkylene oxide in the polyether segment can be in the range of fromabout 20 mole percent to about 75 mole percent.

In one embodiment, the two-component formulation may comprise of acatalyst-containing concentrate and an oxygen-scavenging resin soldunder the trademark OxyClear® manufactured by Auriga Polymers Inc., 4235South Stream Blvd., Charlotte, N.C. 28217. In certain embodiments, thecatalyst-containing concentrate is referred to herein as “Merge” or“Merge 2310™” and the oxygen scavenging component is referred to hereinas “BB-10™” or “Merge 3500™” which are manufactured by Auriga Polymers,Inc.

In certain embodiments where the particular embodiments where a BB-10™component is at least part of the oxygen scavenging component, theBB-10® component can be present in a total concentration of at leastabout 1.0%, by weight, of the multi-layer container. Also, in certainembodiments where the BB-10™ component is the oxygen scavengingcomponent, the multi-layer container does not comprise a reducingsulfite salt or an oxidizable metal such as iron, zinc, copper,aluminum, or tin. In certain embodiments where BB-10™ component is atleast part of the oxygen scavenging component, the multi-layer containerdoes not comprise an electrolyte component. In certain embodiments whereBB-10™ component is at least part of the oxygen scavenging component,the multi-layer container does not comprise a water-absorbent binder.

It is to be understood that, in other embodiment, other scavengingcomponents may be used. For instance, the scavenging component mayinclude a partially aromatic polyamide with a copolyester comprising ametal sulfonate salt. Also, in certain other embodiments, suitableoxygen scavenger components can include oxidizable polymers.

Catalyst-Containing Concentrates

In certain embodiments, the catalyst-containing concentrate may compriseone or more suitable oxidation catalysts. Also, in certain embodiments,the particular catalyst-containing concentrate that is useful in themulti-layer container can be varied, depending on the particular oxygenscavenging component that is used. In particular embodiments, theoxidation catalyst generally comprises a transition metal selected fromcobalt, copper, rhodium, ruthenium, palladium, tungsten, osmium,cadmium, silver, tantalum, hafnium, vanadium, titanium, chromium,nickel, zinc, and manganese. The metal may be in the form of a salt.Suitable counter ions for the metal may include carboxylates (such asneodecanoates, octanoates, stearates, acetates, naphthalates, lactates,maleates, acetylacetonates, linoleates, oleates, palminates, or 2-ethylhexanoates), oxides, borides, carbonates, chlorides, dioxides,hydroxides, nitrates, phosphates, sulfates and silicates. In particularembodiments, the oxidation catalyst comprises cobalt stearate or cobaltacetate. In a particular embodiment, the oxidation catalyst (such ascobalt stearate or cobalt acetate) is present in a total concentrationnot exceeding 3%, by weight, of the multi-layer container.

It is to be understood that the oxidation catalyst is generally blendedwith a polymeric resin in order to form the catalyst-containingconcentrate. In certain embodiments, the polymeric resin is compatiblewith both the outer CPET layer and the inner layer such that no adhesivematerial is needed when forming the multi-layer container.

In one embodiment, the catalyst-containing concentrate can be a materialsold under the trade names Merge and Merge-2310 manufactured by AurigaPolymers, Inc.

Method of Forming “Active or Middle,” Layers

In one method for forming the middle layer, the oxygen scavengingcomponent and the catalyst-component concentrate are blended together inan extruder. No triggering agent is necessary to begin oxygenscavenging. The oxygen scavenger component and the catalyst-containingconcentrate may be blended with one or more additional polymeric resinsto form an active layer for the oxygen-scavenging multi-layercontainers. Suitable additional resins include CPET, APET, PP, EVOH,HDPE, PVC, LDPE, PS, acrylic, nylon, polycarbonate, polylactic acid,ABS, or mixtures thereof. In embodiments where the oxygen scavengercomponent and the catalyst-containing concentrate are not blended withadditional resins, the middle layer has an oxygen scavengercomponent-to-catalyst-containing concentrate ratio ranging from about1:99, 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:60, 40:60, 50:50,55:45, 60:40. 65:35, 70:30, 75:30, 80:20, percent, by weight, of themiddle layer. In particular examples stated herein, the ratio is about5:95, 10:90, 20:80, 25:75, 30:70, 33:67, 40:60, or 50:50 percent, byweight, of the middle layer. Other scavenging component-to-concentrateratios are possible; however, in certain embodiments, the multi-layercontainers disclosed herein has a scavenging component-to-concentrateratio of at least 2:98 percent, by weight, of the middle layer.

In addition, any of the layers (outer, middle and/or inner) in themulti-layer container may comprise additional additives. Examples ofsuch possible additives are dyes, pigments, fillers, branching agents,reheat agents, anti-blocking agents, anti-oxidants, anti-static agents,biocides, blowing agents, coupling agents, flame retardants, heatstabilizers, impact modifiers, UV and visible light stabilizers,crystallization aids, lubricants, plasticizers, drying agents,processing aids, acetaldehydes or other scavengers, and slip agents, ormixtures thereof. Other additives are possible. In addition, any of thelayers in the container, including the layer comprising the scavengingcomponent and the catalyst-containing concentrate, may be foamed. Anysuitable polymeric foaming technique, such as bead foaming or extrusionfoaming, can be utilized to accomplish the foaming. A foamed resin layercan be adhered to a solid resin layer by a suitable method. Also, any ofthe layers may further comprise a passive barrier such as a metalizedpolyolefin, a silica-coated polyester, or aluminum foil. Further, anylayer may comprise an anti-microbial agent to help preserve foods, orsilicone to prevent sticking during processing.

Methods of Making Multilayer Containers (or Articles)

To manufacture the multi-layer container disclosed herein, the layersare blended together at the desired thickness of each layer into amulti-layered material, such as a film, sheet, or preform, through, forexample, coextrusion, coinjection, coating or lamination. Themulti-layered material is then stretch blow molded, “melt-to-mold” orthermoformed into a multi-layer container or other fabricated articleusing either single-stage or multi-stage blow molding or single-stage ormulti-stage thermoforming.

Also described herein is a method of producing an oxygen-scavengingmulti-layer container. The method includes the steps of producing anactive layer by blending at least one oxygen-scavenging component withat least one catalyst-containing concentrate at a specific ratio andextruding the active layer. The active layer can be extruded adjacentone or more other polymeric resins to form a multi-layer container. Incertain embodiments, the multi-layer container can be formed by asuitable process (such as, but not limited to thermoforming, stretchblow molding and melt-to-mold processing). In general, the melt-to-moldprocess, a molten, crystallizable polyester composition film isthermoformed and crystallized by cooling to a temperature between thepolyester Tg and the polyester Tm. In general, thermoforming includesthe step of pulling a plastic sheet from a roll over a die or mold ofthe object to be formed, then sealing the sheet along the periphery ofthe mold. The plastic sheet is then heated to render it pliable, andpressure is applied to the sheet forcing the sheet into the mold.Alternatively a vacuum is drawn from below the sheet evacuating the airin the space between the mold surface and the sheet surface therebydrawing the surface of the sheet into the shape of the mold.Additionally, pressure and vacuum can be used together to form thearticle. When the heated sheet is expanded into and held against thecontours of the mold and allowed to cool, the sheet retains the detailsof the mold upon removal.

Further disclosed herein is a method of controlling the oxygenscavenging incubation period of a multi-layer container. The methodinvolves adjusting the scavenging component-to-concentrate ratio in theactive layer of a multi-layer container.

Examples of suitable other fabricated articles in addition tomulti-layer containers include, but are not limited to, films, sheets,tubing, pipes, fibers, thermoformed articles, or flexible bags. Themulti-layer articles can also be used on as layers, coatings, bottle capliners, sheet inserts, gaskets, sealants, and the like.

Non-limiting examples of products which can be packaged in suchmulti-layer containers include not only food and beverage, but alsoother oxygen sensitive materials such as pharmaceuticals, medicalproducts, corrodible metals or products such as electronic devices, andthe like.

It is also to be understood that in most embodiments, the multi-layercontainer made by this process does not need an external triggeringmechanism such as ultraviolet light or water in order to begin oxygenscavenging.

Crystalline Poly(Ethylene terephthalate) (CPET)

In certain embodiments, at least one of the outer and/or inner layers ofthe multi-layer contain is comprised of a crystalline poly(ethyleneterephthalate) CPET polymer material. In many cases, CPET multi-layercontainers, and articles made therefrom, are opaque because of thecrystallinity of the polymer. Also due to the crystallinity, CPETmulti-layer containers have high heat resistance, are suitable forretort sterilization at temperatures as high as desired, such as 260° F.or higher, and can be used in microwave ovens or conventional ovens(400° F.).

In addition, CPET multi-layer containers are also suitable for use inhot fill sterilization processes (185-194° F.) and other sterilizationprocesses. By contrast, embodiments comprising APET in both the innerand outer layer are glass-clear but have low heat resistance. CPET isalso less subject to deformation under stress than APET. A variety offabricated multi-layer containers comprising both CPET and APET ispossible due to the variability of suitable materials, concentrations,and thicknesses. For example, in certain embodiments, a multi-layercontainer comprises CPET in the outer layer, APET in the inner layer,and has a total thickness of about 10 mils to about 30 mils with a layerthickness ratio from outer to inner of any of 60:20:20, 60:13:27,60:15:25, 60:10:30, 40:20:40, or 20:20:60. Effectively, the multi-layercontainer disclosed herein comprising CPET is a high-heat oxygenbarrier.

In certain embodiments, the synthesis of CPET starts with either anesterification reaction between terephthalic acid and ethylene, or atransesterification reaction between ethylene glycol and dimethylterephthalate. The monomer product is then polymerized into PET througha condensation process with either water or methanol as the byproduct.Once polymerized, the PET material is crystallized. In one method, thePET material is submerged in water, heated to an elevated temperatureknown as the glass transition temperature, and not quenched rapidly.This causes the polymer to turn opaque due to the formation ofcrystallized aggregates of un-oriented polymer. Crystallization of theheated PET material can also be stress-induced. If heated PET materialis dried too rapidly, however, it emerges in an amorphous state as APET.

One feature of the multi-layer container described herein is that themulti-layer container's incubation period before oxygen absorptionbegins can be adjusted by altering the composition of the middle layer,or active layer, that contains the scavenging component andcatalyst-containing concentrate.

It is to be noted that, for particular embodiments, the incubationperiod can be lengthened or shortened by varying the ratio of scavengingcomponent to catalyst-containing concentrate in the middle layer. Thatis, the less amount of catalyst present in the middle layer, the longerthe incubation time of the multi-layer container's oxygen scavenging. Asan example, a multi-layer container having a layer thickness ratio of60:20:20 with CPET in the outer layer, APET in the inner layer, and ascavenging component-to-concentrate ratio of 20:80 percent by weight ofthe middle layer, begins to absorb oxygen without a notable incubationperiod. An otherwise identical multi-layer container having a scavengingcomponent-to-concentrate ratio of 40:60 percent by weight of the middlelayer begins to absorb oxygen after an incubation period of about 50days.

In certain embodiments, to ensure that the container does not scavengeduring inventory (i.e., before being used by the food manufacturer), thescavenging component-to-concentrate ratio can be in the range of about2-to-about-98. Thus, disclosed herein is a method of controlling theincubation period of an oxygen-scavenging multi-layer container, wherethe method does not need to rely on the use of water or ammonium salts.

Various articles, such as packaging containers for food or beverages,can be fabricated from the multi-layer container. These articles canhave negative oxygen permeation for up to three years and can havecustomized incubation periods adjusted for the approximate amount oftime between production of the multi-layer containers and filling of themulti-layer containers. For example, a multi-layer container that willsit for 50 days in a warehouse before being filled could be made to havea 50-day incubation period, as explained above. This way, themulti-layer containers can be kept inactive during inventory, therebyreducing the amount of oxygen scavenger necessary. In addition, thearticles do not need adhesive and do not show delamination.

In certain embodiments where the cost of the scavenging component ishigh, it is desired to maximize the oxygen absorption capacity per gramof the scavenging component. In certain non-limiting embodiments, wherethe BB-10™ component is at least a part of the scavenging component, anoxygen absorption capacity of 50 cc per gram of BB-10™ component isdesirable. As the examples below demonstrate, increasing theconcentration of scavenging component in the middle layer results in anincrease in the oxygen absorption capacity per gram of scavengingcomponent. For example, where oxygen absorption of 55 cc per gram ofBB-10™ component is accomplished, the BB-10™ component is present atleast about 5%, by weight, of the middle layer.

Further disclosed herein is a method of reducing the headspace oxygen ofa multi-layer container. If the oxygen absorption rate is quicker thanthe oxygen permeation rate through the outer layer, then the container'sheadspace oxygen becomes even lower than the original value at the timeof filling. Headspace oxygen reduction is desirable because suchreduction may eliminate the costly practice of gas flushing theheadspace after filling the container with product.

In certain non-limiting embodiments where the scavenging component isthe BB-10™ component, the oxygen permeation rate through the outer layeris less than 2 cc/100 in²·day·atm, which provides a desirable reductionin headspace oxygen. In one particular embodiment, a multi-layer,container includes at least: an outer layer comprising APET at leastabout 3.6 mils thick, and an outer layer comprising CPET at least about1.5 mils thick.

The duration of headspace oxygen reduction is a function of thescavenging component concentration. The method of reducing the headspaceoxygen of a multi-layer container can include adjusting the thickness ofthe outer layer, the total amount of the scavenging component, or theconcentration of the scavenging component.

EXAMPLES

Certain embodiments of the present invention are defined in the Examplesherein. It should be understood that these Examples, while indicatingpreferred embodiments of the invention, are given by way of illustrationonly. From the above discussion and these Examples, one skilled in theart can ascertain the essential characteristics of this invention, andwithout departing from the spirit and scope thereof, can make variouschanges and modifications of the invention to adapt it to various usagesand conditions.

Some of the following examples reference trial or other identifyingnumbers. Because many parameters and characteristics of the multi-layercontainer disclosed herein are customizable, many alternativeembodiments of the multi-layer container are possible. A series of 17multi-layer containers in accordance with the present disclosure weremanufactured and tested in a variety of manners in comparison with twocontrol containers and three monolayer containers.

For ease of reference when reading the following examples, thecomposition of the various embodiments of the multi-layer container,along with the control and monolayer containers, described in thefollowing examples are given below:

Trial #1: 11 mil APET monolayer container, 0% total BB-10® component.

Trial #2: 11 mil monolayer container with 3% BB-10™, 17% Merge™ and 80%APET, 3% total BB-10™ component.

Trial #3: 6.6 mil APET/2.2 mil (15% BB-10™ +85% Merge™)/2.2 mil APET, 3%total BB-10™ component.

Trial #4: 4.4 mil APET/2.2 mil (15% BB-10™ +85% Merge™)/4.4 mil APET, 3%total BB-10™ component.

Trial #5: 2.2 mil APET/2.2 mil (15% BB-10™ +85% Merge™)/6.6 mil APET, 3%total BB-10™ component.

Trial #6: 11 mil monolayer structure with 2% BB-10™, 18% Merge™ and 80%APET, 2% total BB-10™ component.

Trial #7: 6.6 mil APET/2.2 mil (10% BB-10™+90% Merge™)/2.2 mil APET, 2%total BB-10™ component.

Trial #8: 4.4 mil APET/2.2 mil (10% BB-10™+90% Merge™)/4.4 mil APET, 2%total BB-10™ component.

Trial #9: 2.2 mil APET/2.2-mil (10% BB-10™+90% Merge™)/6.6 mil APET, 2%total BB-10™ component.

Trial #10: 11 mil monolayer structure with 1% BB-10™, 19% Merge™ and 80%APET, 1% total BB-10™ component.

Trial #11: 6.6 mil APET/2.2 mil (5% BB-10™+95% Merge™)/2.2 mil APET, 1%total BB-10™ component.

Trial #12: 4.4 mil APET/2.2 mil (5% BB-10™+95% Merge™)/4.4 mil APET, 1%total BB-10™ component.

Trial #13: 2.2 mil APET/2.2 mil (5% BB-10™+95% Merge™)/6.6 mil APET, 1%total BB-10™ component.

Trial #14: 6.6 mil APET/2.2 mil (25% BB-10™+75% Merge™)/2.2 mil APET, 5%total BB-10™ component.

Trial #15: 6.6 mil APET/1.7 mil (33% BB-10+67% Merge™)/2.7 mil APET, 5%total BB-10™ component.

Trial #16: 6.6 mil APET/1.1 mil (50% BB-10™+50% Merge™)/3.3 mil APET, 5%total BB-10™ component.

CPET Control: 20 mil CPET, 0% total BB-10™ component.

#10446: 12 mil CPET/4 mil (10% BB-10™+90% Merge™)/4 mil APET, 2% totalBB-10™ component.

#Oxy 2: 12 mil CPET/2 mil (20% BB-10™+80% Merge™)/6 mil APET, 2% totalBB-10™ component.

#Oxy 3: 12 mil CPET/4 mil (20% BB-10™+80% Merge™)/4 mil APET, 4% totalBB-10™ component.

#Oxy 4: 12 mil CPET/2.7 mil (30% BB-10™+70% Merge™)/5.3 mil APET, 4%total BB-10™ component.

#Oxy 5: 12 mil CPET/2 mil (40% BB-10™+60% Merge™)/6 mil APET, 4% totalBB-10™ component.

Example 1 Oxygen Ingress

A CPET multi-layer container having a volume of 93 cc, a surface area of15.25 in², and a sidewall thickness of 20 mils was fabricated and testedside by side with a CPET control container. An OxyDot® oxygen sensor wasglued on the clear inner surface of a glass plate inside the containers,and the containers were then sealed. During sealing, the containers wereflushed with nitrogen to 1% headspace oxygen.

As shown in FIG. 1, the headspace oxygen of the control containerincreased after 1,000 days from 1.37% to 5.56%, while that of the CPETmulti-layer container decreased from 1.03% to 0.26%. These resultsclearly demonstrate that the CPET multi-layer container is superior notonly to any plastics-based containers, but also to metal cans and glassbottles. A good result was achieved with a very high surface to volumeratio (16.4 in²/100 cc or 15.25 in²/93 cc) multi-layer container havinga fairly thin side wall (20 mils).

Example 2 Barrier Properties

A CPET multi-layer container having a volume of 297 cc, a surface areaof 35.3 in², and a sidewall thickness of 19 mils, was filled with about90% water to have about 10% empty headspace. A SiO_(x)-coated batherlidding film with an OxyDot® oxygen sensor glued on the inner surfacewas heat-sealed on the container. The same procedure was followed for aCPET control container and a PP/EVOH container, to be tested side byside with the CPET multi-layer container. During water filling, thecontainers were flushed with nitrogen to 5% headspace oxygen. Thecontainers were then retorted at 260° F. for 45 minutes.

As shown by FIG. 2, the control container and the PP/EVOH containershowed a steady increase of oxygen concentration while the CPETmulti-layer container showed a steady decrease of oxygen concentration.At day 20, the headspace oxygen change of the PP/EVOH container, thecontrol container, and the CPET multi-layer container was +1.5%, +0.8%,and −0.3%, respectively. The poor oxygen barrier property of the PP/EVOHcontainer shortly after retort is due to the retort shock effect; theretort causes high moisture content in EVOH. As the barrier property ofEVOH recovered after about 80 days, the PP/EVOH container had loweroxygen concentration than the control container. At day 320, theheadspace oxygen change of the control container, the PP/EVOH container,and the CPET multi-layer container was +5.0%, +2.2%, and −4.0%,respectively. This result clearly demonstrates that the CPET multi-layercontainer is superior to the commercial PP/EVOH container. Furthermore,the results show the headspace oxygen of the CPET multi-layer containersteadily decreases, in contrast to perfect barrier packages such asmetal cans or glass bottles, which can only keep the headspace oxygenunchanged.

Example 3 Multi-Layer v Mono Layer

The oxygen absorption of a multi-layer container was compared to that ofa monolayer container. The container sidewall was pulverized to fineparticles and placed in a sealed glass container. The oxygenconcentration inside the glass container was measured periodically by anon-invasive oxygen analyzer sold by Oxysense Inc. The glass containercontaining an APET control container sample remained at 21% oxygen whilethe multi-layer container's oxygen absorption was lower.

As seen in FIGS. 5A-5B, FIGS. 6A-6B and FIGS. 7A-7B, the monolayercontainers containing BB-10™ component (trials #10, #6 and #2) did notabsorb oxygen at all, while the multi-layer containers containing BB-10™component (trials #12, #8 and #4) absorbed oxygen. While not wishing tobe bound by theory, it is now believed by the inventors herein that thehost APET polymer in the monolayer container destroys the efficacy ofthe BB-10™ component/Merge™ component oxygen scavenger completely.

Example 4 Oxygen Permeation

Oxygen permeation was compared between a multi-layer container, an APETcontrol container, and a monolayer container. The containers were sealedwith a glass plate in a low oxygen chamber. The initial headspace oxygeninside the containers was about 1-2%. The headspace oxygen concentrationwas measured periodically by a non-invasive oxygen analyzer sold byOxysense Inc. to obtain the oxygen permeation rate. The oxygenpermeation of the APET control container and the monolayer containerincreased with time while the multi-layer container's oxygen permeationwas far lower, sometimes negative.

As seen in FIGS. 8A-8B, FIGS. 9A-9B and FIGS. 10A-10B, the monolayercontainer containing BB-10® component (trials #10, #6 and #2) did notabsorb oxygen at all while the multi-layer container containing BB-10™component (trials #12, #8 and #4) absorbed oxygen. The host APET polymerin the monolayer structure destroyed the efficacy of the BB-10™component/Merge™ component oxygen scavenger completely. By incorporatingthe BB-10 component™/Merge™ component oxygen scavenger in a separatelayer in the multi-layer container, the oxygen absorption efficacy ofthe BB-10™ component/Merge™ component oxygen scavenger is preserved.

Example 5 Oxygen Absorption Capacity

The concentration effect on oxygen absorption capacity was determined.The sidewall of each of an APET control container and a multi-layercontainer was pulverized to fine particles and placed in a sealed glasscontainer. The headspace oxygen of the glass container containing theAPET control container sample remained at 21% while that containing themulti-layer container was lower. The percent reduction of the oxygenheadspace can be converted to the amount of oxygen absorbed. Since theamount of BB-10™ component in each pulverized sample is known, one cancalculate the oxygen absorption capacity (cc/g of BB-10™ component). Thesteady state values after 130 days are shown in FIG. 11A.

The oxygen absorption capacity of the BB-10™ component/Merge™ componentformulation increases with the BB-10™ component concentration in themiddle layer. In other words, for the same amount of BB-10™ component,one can increase the efficacy of the BB-10™ component/Merge™ componentformulation by concentrating BB-10™ component in a thin layer of amulti-layer structure instead of dispersing BB-10™ component in a thickmonolayer structure.

In certain embodiments, since the particular oxygen scavenger BB-10™component is much more expensive than other components in a plasticcontainer, it is desired to maximize the oxygen absorption capacitywhile using a lesser amount of the expensive oxygen scavenger componentin order to be cost competitive with other barrier systems. In certainembodiments, an oxygen absorption capacity of 50 cc per gram of BB-10™component is desirable.

FIGS. 11A-11B and FIG. 12, show specific embodiments where the BB-10™component concentration in the middle layer is higher than 5%, byweight.

Example 6 Headspace Oxygen Absorption

The effect of layer structure on headspace oxygen absorption wasdetermined by measuring oxygen permeation in containers with varyinglayer structures. The containers were sealed with a glass plate in a lowoxygen chamber. The initial headspace oxygen inside the containers wasabout 1-2%. The headspace oxygen concentration was measured periodicallyby a non-invasive oxygen analyzer sold by Oxysense Inc. to obtain theoxygen permeation rate. The headspace oxygen of the APET controlcontainer increased with time while that of the multi-layer containershowed a reduced oxygen permeation rate or even a negative permeation.

As seen in FIGS. 13A-13B, FIGS. 14A-14B and FIGS. 15A-15B, the APETcontrol #1 container did not absorb oxygen at all while the multi-layercontainers containing BB-10 component™/Merge™ component absorbed oxygen.Containers having a 2.2 mil APET outer layer, a 4.4 mil APET outerlayer, and a 6.6-mil APET outer layer were also tested.

The effect of the outer layer permeation rate on the headspace oxygenreduction is summarized in the table shown in FIG. 16.

From these results, it is determined that the oxygen permeation ratethrough the outer layer should be less than 2 cc/100 in²·day·atm for theBB-10™ component/Merge™ component formulation to reduce the headspaceoxygen inside a container. Furthermore, the total BB-10™ componentconcentration is the factor which determines the duration of oxygenheadspace absorption (e.g., #4, #8 vs. #12 in FIGS. 14 and #3, #7 vs.#11 in FIG. 15). The oxygen permeation rate is a function of materialproperties and layer thickness. In one embodiment, in order to achievethe 2 cc/100 in²·day·atm requirement, a 3 mil APET outer layer was used,and a 1.5 mil CPET outer layer was sufficient.

Example 7 Scavenging Component/Catalyst Component Ratio in MultilayerContainer as Affecting Oxygen Absorption Incubation Time

The effect of the scavenging component-to-catalyst concentrate ratio wasstudied by measuring the oxygen absorption of containers with varyingscavenging component-to-catalyst concentrate ratios. The sidewalls ofseveral containers were pulverized into fine particles and placed in asealed glass container. The oxygen concentration inside the glasscontainer was measured periodically by a non-invasive oxygen analyzersold by Oxysense Inc. The glass container containing the APET controlcontainer sample remained at 21% while that containing the multi-layercontainer sample was lower. The difference between 21% and that of themulti-layer container is shown in FIGS. 17A-22B.

FIG. 17A is a graph showing the effect of the scavengingcomponent-to-catalyst concentrate ratio on the oxygen absorptioncontinues over time for multi-layer container (#10446) having thelayers: 12 mil CPET/4 mil blend (10% BB-10™ component+90% Merge™component)/4 mil APET; where the container has 2% total BB-10™component, and for multi-layer container (#Oxy 2) having the layers: 12mil CPET/2 mil blend (20% BB-10 component+80% Merge™ component)/6 milAPET; where the container has 2% total BB-10™ component, for over 100days. FIG. 17B is a table of the data shown in FIG. 17A.

FIG. 18A is a graph showing the effect of the storage time-on the oxygenabsorption over time for multi-layer container (#10446) having thelayers: 12 mil CPET/4 mil blend (10% BB-10™ component+90% Merge™component)/4 mil APET; where the container has 2% total BB-10™component. FIG. 18B is a table of the data shown in FIG. 18A.

FIG. 19A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy2) having thelayers: 12 mil CPET/2 mil blend (20% BB-10™ component+80% Merge™component)/6 mil APET; where the container has 2% total BB-10™component. FIG. 19B is a table of the data shown in FIG. 19A.

FIG. 20A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy 3) having thelayers: 12 mil CPET/4 mil blend (20% BB-10™ component+80% Merge™component)/4 mil APET; where the container has 4% total BB-10™component. FIG. 20B is a table of the data shown in FIG. 8A.

FIG. 21A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy 4) having thelayers: 12 mil CPET/2.7 mil blend (30% BB-10™ component+70% Merge™component)/5.3 mil APET; where the container has 4% total BB-10™component. FIG. 21B is a table of the data shown in FIG. 21A.

FIG. 22A is a graph showing the effect of the storage time on the oxygenabsorption over time for multi-layer container (#Oxy 5) having thelayers: 12 mil CPET/2 mil blend (40% BB-10™ component+60% Merge™component)/6 mil APET; where the container has 4% total BB-10™component. FIG. 22B is a table of the data shown in FIG. 22A.

This experiment was first conducted 7 days after the containers weremade. The same experiment was then repeated 42 days after the containerswere made. From FIGS. 18A-22B, it is now shown that that the containers,except Oxy 5, after 42-day storage absorb oxygen immediately while thoseafter 7-day storage have an incubation time in oxygen absorption.

The incubation time based on the first experiment (7-day storage) issummarized in the table shown in FIG. 23, summarizing the data of FIGS.18A-18B, FIGS. 19A-19B, FIGS. 20A-20B, FIGS. 21A-21B and FIGS. 22A-22Bshowing the effect of varying the scavenging component-to-catalystconcentrate ratio on the oxygen absorption incubation time.

The incubation time increased with the BB-10™ component/Merge™ componentratio. Container Oxy 5, which has a 40:60 BB-10™ component/Merge™component ratio, had a 60-day incubation time. The long incubation timeof container Oxy 5 was also confirmed by the second experiment. After42-day storage, container Oxy 5 still had a 20-day incubation time.Since the incubation time of containers #10446, Oxy 2, Oxy 3, Oxy 4 andOxy 5 were all less than 42 days, those containers showed no incubationtime during the second experiment.

Example 8 Scavenging Component/Catalyst Component Ratio in MultilayerContainer as Affecting Oxygen Permeation

The effect of varying scavenging polymer-to-concentrate ratio on oxygenpermeation was determined by measuring the oxygen permeation in a seriesof containers with different scavenging polymer-to-concentrate ratios.The containers were sealed with a glass plate in a low oxygen chamber.The initial headspace oxygen inside the containers was about 1-2%. Theheadspace oxygen concentration was measured periodically by anon-invasive oxygen analyzer sold by Oxysense Inc. to obtain the oxygenpermeation rate. The headspace oxygen of the APET control containerincreased with time while that of the multi-layer container showedreduced oxygen permeation or even negative permeation.

This experiment was first conducted 14 days after the containers weremade. The same experiment was repeated 71 days after the containers weremade. From FIGS. 24-26. It is determined that the containers after71-day storage absorbed oxygen immediately while those after 14-daystorage had an initial positive oxygen permeation due to the incubationtime of oxygen absorption. The transition time of changing from positivepermeation to negative permeation is determined by the incubation time.

The transition time based on the first experiment (14-day storage) issummarized in the table shown in FIG. 27. As can be seen from theseexperiments, the transition time increases with the scavengingpolymer-to-concentrate ratio.

Certain embodiments of the multi-layer container disclosed herein aredefined in the examples herein. It should be understood that theseexamples, while indicating particular embodiments of the invention, aregiven by way of illustration only. From the above discussion and theseexamples, one skilled in the art can ascertain the essentialcharacteristics of this invention, and without departing from the spiritand scope thereof, can make various changes and modifications of theinvention to adapt it to various usages and conditions. Various changesmay be made and equivalents may be substituted for elements thereofwithout departing from the essential scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof.

What is claimed is:
 1. A multi-layer container comprising an outerlayer, an inner layer, and at least one middle layer interposedtherebetween; the middle layer including a blend of: i) at least oneoxygen-scavenging component, and ii) at least one catalyst-containingconcentrate; wherein middle layer contains at least one catalysttransition metal up to about 3%, by weight, of the multi-layercontainer.
 2. The multi-layer container of claim 1, wherein thecatalyst-containing concentrate includes one or more oxidation catalyst.3. The multi-layer container of claim 1, wherein the catalyst-containingconcentrate depends on the scavenging component.
 4. The multi-layercontainer of claim 1, wherein the catalyst-containing concentratedepends on the ability to co-process (e.g., co-extrusion orco-injection) with the scavenging component.
 5. The multi-layercontainer of claim 1, wherein the catalyst-containing concentrateincludes a transition metal selected from cobalt, copper, rhodium,ruthenium, palladium, tungsten, osmium, cadmium, silver, tantalum,hafnium, vanadium, titanium, chromium, nickel, zinc, and manganese. 6.The multi-layer container of claim 1, wherein the catalyst-containingconcentrate includes a transition metal in the form of a salt.
 7. Themulti-layer container of claim 1, wherein the catalyst-containingconcentrate includes a transition metal in the form of a salt, andwherein counter ions for the metal include one or more of carboxylates,including neodecanoates, octanoates, stearates, acetates, naphthalates,lactates, maleates, acetylacetonates, linoleates, oleates, palminates,and 2-ethyl hexanoates; oxides; borides; carbonates; chlorides;dioxides; hydroxides; nitrates; phosphates; sulfates; and, silicates. 8.The multi-layer container of claim 1, wherein the catalyst-containingconcentrate includes at least one of cobalt stearate or cobalt acetatethat is present in a total concentration not exceeding about 3%, byweight, of the multi-layer container.
 9. The multi-layer container ofclaim 1, wherein the catalyst-containing concentrate is comprised of anoxidation catalyst blended with a polymeric resin.
 10. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 5:95.
 11. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 10:90.
 12. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 20:80.
 13. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 30:70.
 14. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 40:60.
 15. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 50:50.
 16. The multi-layercontainer of claim 1, wherein a ratio of oxygen-scavenging component tocatalyst-containing concentrate is about 60:40.
 17. The multi-layercontainer of claim 1, wherein a total concentration of oxygen-scavengingcomponent in the middle layer is at least about 10%, by weight, of themulti-layer container.
 18. The multi-layer container of claim 1, whereina total concentration of oxygen-scavenging component in the middle layeris at least about 5%, by weight, of the multi-layer container.
 19. Themulti-layer container of claim 1, wherein a total concentration ofoxygen-scavenging component in the middle layer is at least about 3%, byweight, of the multi-layer container.
 20. The multi-layer container ofclaim 1, wherein a total concentration of oxygen-scavenging component inthe middle layer is at least about 2%, by weight, of the multi-layercontainer.
 21. The multi-layer container of claim 1, wherein a totalconcentration of oxygen-scavenging component in the middle layer is atleast about 1%, by weight, of the multi-layer container.
 22. Themulti-layer container of claim 1, wherein a total concentration ofoxygen-scavenging component in the middle layer is at least about 0.5%,by weight, of the multi-layer container.
 23. The multi-layer containerof claim 1, wherein the outer layer of the multi-layer container has anoxygen permeation rate of no greater than about 3 cc O₂/100 in²·day·atm.24. The multi-layer container of claim 1, wherein the outer layer of themulti-layer container has an oxygen permeation rate of no greater thanabout 2 cc O₂/100 in²·day·atm.
 25. The multi-layer container of claim 1,wherein the outer layer of the multi-layer container has an oxygenpermeation rate of no greater than about 1.5 cc O₂/100 in²·day·atm. 26.The multi-layer container of claim 1, wherein the outer layer of themulti-layer container has an oxygen permeation rate of no greater thanabout 1 cc O₂/100 in²·day·atm.
 27. The multi-layer container of claim 1,wherein the outer layer of the multi-layer container has an oxygenpermeation rate of no greater than about 0.5 cc O₂/100 in²·day·atm. 28.The multi-layer container of claim 1, wherein the outer layer of themulti-layer container has an oxygen permeation rate of no greater thanabout 0 cc O₂/100 in²·day·atm.
 29. The multi-layer container of claim 1,wherein the outer layer of the multi-layer container has an oxygenpermeation rate of less than about 0 cc O₂/100 in²·day·atm.
 30. Themulti-layer container of claim 1, wherein the multi-layer container hasan oxygen headspace absorption effect of about 0 cc O₂ ingress afterabout 5 days.
 31. The multi-layer container of claim 1, wherein themulti-layer container has an oxygen headspace absorption effect of lessthan about 0 cc O₂ ingress after about 5 days.
 32. The multi-layercontainer of claim 1, wherein the multi-layer container has an oxygenheadspace absorption effect of more than about 0.3% headspace oxygenreduction after about 20 days.
 33. The multi-layer container of claim 1,wherein the multi-layer container has an oxygen absorption effect ofthat increases over time after about 5 days after manufacturing of themulti-layer container.
 34. The multi-layer container of claim 1, whereinthe middle layer has an oxygen-scavenging component tocatalyst-containing concentrate ratio of greater than about 0.05. 35.The multi-layer container of claim 1, wherein substantially no adhesivematerial is interposed between the middle layer and the outer layerand/or the middle layer and the inner layer.
 36. The multi-layercontainer of claim 1, wherein at least one of the outer layer and theinner layer is comprised of an amorphous poly(ethylene terephthalate)polymer (APET).
 37. The multi-layer container of claim 1, wherein boththe outer layer and the inner layer are comprised of an amorphouspoly(ethylene terephthalate) polymer (APET).
 38. The multi-layercontainer of claim 1, wherein at least one of the inner layer and theouter layer is comprised of amorphous poly(ethylene terephthalate)polymer (APET), and the blend of the oxygen-scavenging polymer and thecatalyst-containing concentrate is present in the middle layer at abouta 50:50 ratio.
 39. The multi-layer container of claim 1, wherein atleast one of the inner layer and the outer layer is comprised ofamorphous poly(ethylene terephthalate) polymer (APET), and the blend ofthe one oxygen-scavenging polymer and the catalyst-containingconcentrate is present in the middle layer at about a 50:50 ratio; andwherein the middle layer has a thickness of about 0.5 mil.
 40. Themulti-layer container of claim 1, wherein at least one of the innerlayer and the outer layer is comprised of amorphous poly(ethyleneterephthalate) polymer (APET), the blend of the one oxygen-scavengingpolymer and the catalyst-containing concentrate is present in the middlelayer at about a 50:50 ratio; and, the multi-layer container having anoxygen absorption of about 50 cc O₂, per gram of oxygen-scavengingpolymer, present in the multi-layer container.
 41. The multi-layercontainer of claim 1, wherein at least one of the outer layer and theinner layer is comprised of an amorphous poly(ethylene terephthalate)polymer (APET), and the outer layer has a thickness of about 1 mil ormore.
 42. The multi-layer container of claim 1, wherein at least one ofthe outer layer and the inner layer is comprised of an amorphouspoly(ethylene terephthalate) polymer (APET), and the oxygen-scavengingpolymer in the middle layer is present at least about 0.5%, by weight,of the multi-layer container.
 43. The multi-layer container of claim 1,wherein at least one of the outer layer and the inner layer is comprisedof an amorphous poly(ethylene terephthalate) polymer (APET), and theoxygen-scavenging component to catalyst-containing concentrate in themiddle layer is present at least about 1%, by weight, of the multi-layercontainer.
 44. The multi-layer container of claim 1, wherein at leastone of the outer layer and the inner layer is comprised of an amorphouspoly(ethylene terephthalate) polymer (APET), and the oxygen-scavengingpolymer in the middle layer is present at least about 2%, by weight, ofthe multi-layer container.
 45. The multi-layer container of claim 1,wherein at least one of the outer layer and the inner layer is comprisedof an amorphous poly(ethylene terephthalate) polymer (APET), and theoxygen-scavenging component polymer in the middle layer is present atleast about 2%, by weight, of the multi-layer container.
 46. Themulti-layer container of claim 1, wherein at least one of the outerlayer and the inner layer is comprised of an amorphous poly(ethyleneterephthalate) polymer (APET), and a ratio of the oxygen-scavengingcomponent present to catalyst-containing concentrate in the middle layeris about a 5:95 ratio.
 47. The multi-layer container of claim 1, whereinat least one of the outer layer and the inner layer is comprised of anamorphous poly(ethylene terephthalate) polymer (APET), and theoxygen-scavenging component present at least about 2% or greater, byweight, of the multi-layer container.
 48. The multi-layer container ofclaim 1, wherein at least one of the outer layer and the inner layer iscomprised of an amorphous poly(ethylene terephthalate) polymer (APET),and the multi-layer container has an oxygen absorption of at least about50 cc O₂, per gram of oxygen-scavenging component.
 49. A multi-layercontainer comprising an outer layer, an inner layer, and at least onemiddle layer interposed therebetween; the middle layer including a blendof: i) at least one oxygen-scavenging component, and ii) at least onecatalyst-containing concentrate; wherein middle layer contains at leastone catalyst transition metal up to about 3%, by weight, of themulti-layer container; the multi-layer container having: i) a ratio ofoxygen-scavenging component to catalyst-containing concentrate of about5:95; ii) a total concentration of oxygen-scavenging component in themiddle layer of at least about 0.5%, by weight, of the multi-layercontainer; iii) an oxygen permeation rate of the outer layer no greaterthan about 3 cc O₂/100 in²·day·atm; iv) an oxygen headspace absorptioneffect of about 0 cc O₂ ingress after about 5 days; and v) an oxygenabsorption effect of that increases over time after about 5 days aftermanufacturing of the multi-layer container.
 50. A method of making themulti-layer container, comprising: a) providing a middle layer includinga blend of: i) at least one oxygen-scavenging component; and, ii) atleast one catalyst-containing concentrate that contains at least onecatalyst transition metal up to about 3%, by weight, of the multi-layercontainer; and, b) interposing the middle layer between at least oneouter layer and at least one inner layer without the use of an adhesivematerial.